1. Negative emission technologies: technologies that remove the carbon dioxide content in the atmosphere

2. The role of the United Nations (UN) in addressing global environmental issues

• finds solutions to address issues related to global climate change by sponsoring international conferences and agreements signed by the global community
• secures the adequate supply of clean drinking water
• protects the ozone layer by banning the use of chlorofluorocarbons, which causes the thinning of the ozone layer 
• bans the use of toxic chemical substances such as DDT pesticides